Automatic grab



H. REECHMANN AUTOMATIC GRAB Nov. 8, 1932.

Filed Feb. 25, 1931 2 Sheets-Sheet l I invemar: /7f efah mam;

LSAZQ NW. 1932. H. REICHMANN AUTOMATIC GRAB Filed Feb. 25, 1931 2Sheets-Sheet 2 l'n e efifwz #8 (216% Man n Patented Nov. 8, 1932 UNITEDSTATES;

rear-2e.

nnrnnrcnnnrcnnann, on nnrsB ne-Rnrrnonr, GERMANY" AUTOMATIC "GR-AC3"ApplicationifilediEebruary25,- 1931, SeriaLNo. 518,176; and infGerm-anyEebruary28, 1930.

This; invention relates to an automatic grabin which-the-bucketsare'linked on. a,

rigid. pulley box-to; pressure bars. Inall known .bucket grabs thegrabbuckets which 5 are linkedon a p ulleybox to pressure bars are spanof the jaws. The grab buckets of the known systems cannot thereforepenetrate independently of one another more or lessdeeply ;into thematerialto be dealt with according to the resistance of the latter.

In 'contradistinction thereto, according to the invention thegrabbucketsare provided insteadof with the internal pivot with bucket arms whicharerigidly connected to them, ex.-

tend into the pulley box and are capable 0f moving; in thepulley boxindependently of one another,- By this means each of the buck.-

ets can swing independently about its onev pivot and. adapt-itself,independently of the other bucket, to resistance which it happens tostrike. Whom entering; the v material to be grabbed.

Preferably the grab arms are guided in sliding paths provided on thepulley box, the main function of which is to enable the grab buckets toopen uniformly, the positive opening of the grab being ensured bythedischarge ropes forming a pulley block arrangement between the end ofthe bucket arms and a point on the pulley box.

Such a grab is particularly suitable for unloading sea-going and rivercraft, as, owing to its small overall height, it can be introducedthrough the relatively narrow hatches into the holds, where, owing tothe great span of the jaws, it automatically grabs even the materiallying under the gangways of the ships and not within reach of the grabshitherto used. The new grab has the further advantage that during thefirst half of the closing operation the buckets, owing to the toggleaction of the pressure bars, dig themselves firmly into the materialindependently of one another, while in the second half of the closingoperation .the material seized is shovelled: up, thegrab closing rapidlyIn the faccompanyingdrawings-a constructional exampleof the new grab,isillustrated, ,Eigurel showsthe closed grab infront elevation, onlytheguiding means ofthe discharging ropes beingshown Figure 2 shows thepulleybox withthe;

the gmbisopen, I t

Figure; 3 -shows the grab whenopen, only the guiding means of;theclosing {IOPBS being; ho r Figur 4c .-sh ows the; pulley box with;the. guiding m an or: the loadi g or o ing ropes when the grab isclosed.

Figure 5 is aside elevation offthe closed, grab partly-insection.

The, grab consists. of a rigid 1 pulley; box. a

on which theipressure bars 0, ojarepivoted about; points I), b. Theother end' ofrthei pressure bars are pivotally attachedi t0 the; bucketsL, L. Laterally of the bucketsand; connected rigidly with themarearmstl, Z,"

which extendinto the pulley box, a in which;

they; are movable; independently, of one; an: other. For thispurposetheendsofthearms of; each bucket are connected-togetherby a transverseshaft 6,6: theiree ends of whioh areprovided withrollersfif whichsuitably ngagei groo srg, .9 provide n he: pulley box; The latter arebent ZEIOHlpPEtllS; of angle irons. 'Ilheends-of the bucketarms Z,,Z.'-can th'erefore move inthese cam'grooves; g1, g independentlyotone-another.

he ,cam grooves-g, gfor the shafts;;e, e5 are preferablyso shaped thattheywexten'd in. the first; place fronithe; outside inwardly; in 3:3horizontal direction. or at. a 5 slight inclinas tion, after; whichthey. rise in; the lifting? iirection. The shape of, the camg-roovewvaries. according to the; purpose for which the grab ist'o beused andgthe material to be dealt; with, so ,asyto obtain a! suitable;line of engagement;

The' engagementiis further considerably; a s-;.

sisted bythe fact that the pivots 6,; bf ancL theipressure,barsc, c. inthe-pulley boXl-a. re;- spread out-as fan-as possible, and Withasuitable construction of the: cam grooves 91,19, correspondi-gly. wide spanof; the {opened-grab;

'gniding means forthe';disohargingrope when 7 is obtained and that thepressure bars act as toggles and make the buckets penetrate more readilyinto the material.

For opening and closing the grab two discharging ropes m, m and twoclosin ropes (loading ropes) n, n are employed. For the sake ofclearness in Figures 1 and 2 only the rope guide for the dischargingropes and in Figures 3 and f only the rope guides for the closing ropesare shown. The two discharging ropes m, m are led ina symmetricalarrangement (Figures 1 and 2) in series over guiding pulleys 0, 0 overpulleys h, h and then round pulleys (Z, d and their ends aresecured at sand s in the pulley box a. The pulleys 0, 0 and 72,15 are mountedrigidly on the pulley box a while the pulleys (Z, cl are rotatablymounted on the movable axles e, 6. All the pulleys of the dischargingropes thus lie in one plane, as is shown in Figure 5, in which, for thesakeof simplicity, the pulley h is omitted. In the arrangement shown thedischarge ropes m, m which are secured to the pulley box, together withthe pairs of pulleys h, (Z and h, d form pulley block arrangements. Whenthe ropes m, m are pulled these cause the axles e or e to be displacedoutwardly and downwardly in the guides g, g from the upper positionshown in Fig. 1 (Fig. 2), the movement being limited by stops 2?, 2."(only shown in Fig. l) on the pulleys f, f. In this position the bucketsL, L take up the open position shown in Fig. 3.

The loading ropes n, 11/ coming from the crane cause the closing of thegrab. These are guided in a symmetrical arrangement (Figs. 3 and 4) overguide pulleys p, 29 mounted rigidly on the pulley box a to the groups ofpulleys D, D mounted on the movable axles e, 6. two innermost pulleys D,D each to a group of pulleys .7: or is rotatable about arfixed shaft Kin thepulley box a. After two further turns round the pulleys D, is orD, is, the ends of the loading ropes are-crossed over and secured to theoppositely disposed axles e or e. In Fig. 5 the guide pulley 1) liesbehind the innermost pulley k and the guide pulley p in front of theinnermost rope pulley is. For the sake of simplicity the guide pulley phas been omitted in Fig. 5. The-loading ropes n, 11. together with thegroups of pulleys is, D and 76, D form pulley block arrangements. Whenthese ropesare pulled the grab buckets L, L are moved from the openposition shown in Fig. 3 into the closed position (Fig. 1) the pulleyaxles e, 6 being displaced upwardly in the guides g, g by the pulleyblock arrangements In, D, k, D (Fig. 4). During the closing operationeach bucket L, L can be adjusted independently of the other, the bucketsbeing forced into the material by the pressure bars 0,0 acting inthemanner of toggles. The toggle action here is stronger, the further Theropes passover the the pulleys it, (Z or it, cl in the cam grooves g, guntil the grab is open. 3 During this operation the cam grooves g, '9cause the grab to open uniformly.

What I claim is:

1. An automatic grab with. a. large span having a pulley box, grabbuckets, connectmg rods joining the grab buckets to the pulleybox,lateral pressure bars rigidly secured to the buckets, transverse axlesconnec'ting the free ends of the pressure bars, these free endsprojecting into the pulley box, cam grooves arranged in-the pulley box,in which the ends of the pressure bars are guided, pulleys on themovable axles, pulleys in the pulley box, and ropes between the pulleyson the movable axle and the pulleys in the pulley box for opening andclosing each bucket independently.

2. An automatic grab as claimed in claim 1 1 in which the rigid pressurebars of each bucket are independently guided in the cam grooves in thepulley box.

-3. An automate grab as claimed in-claim 1 having discharging ropesadapted to form a pulley block arrangement between the ends of thebucket arms and a point on the pulley box.

4:. An automatic grab as claimed in claim 1 in which the cam grooves aresmooth and curved.

In testimony whereof I have signed my name to this specification.

HEINRICH REICHMANN.

